It is known to print code numbers unobtrusively on the underside of objects such as canned goods using apparatus comprising fixed, spaced apart guide rails bridging a gap between two aligned conveyor belts. Objects slide along the guide rails pushed by further objects leaving the first conveyor belt and a printing head is moved up and down between the guide rails to apply the code numbers.
With this known arrangement it may be difficult conveniently to achieve rapid, accurate printing insofar as the objects are not moved in a carefully controlled manner during the printing operation.
An object of the present invention is to provide simple apparatus with which it is possible to achieve carefully controlled movement of an object over a printing head.